Crank case lubricating system



p 9, 1933. M. BIRKIGT 1,927,770

CRANK CASE LUBRICATING SYSTEM Filed Feb. 12, 1952 MARC BEMRPUGT Patented Sept. 19, 1933 1,927.7 10; CRANK CASE LUBRICIATI'NG ISY STEM' I I Marc.Birkigt,.-Bois-Golombes; France Application February 12, ashim. 592.565; ff and in Belgium November 12', 1 931j I V I III' 7. Claims. (01.. rare-6');

The present invention relates to:- the lubricat ing portions of crank case assemblies. I

Direct" observation. of the interior of a crank case-during rotation of a crank shaft showsfthat '5; under certain conditions. the air currentspro-- duced by the latter-tend to force the. oil at the bottomof the crank case toward. the center thereof. Inasmuch as the intake 015 the lubricating pump communicates generally with bothextrem-- m ities of the bottom of the crank case, oil. flows thereinto very irregularly and; during certain in-- tervals, not at all. In other words. the center of the crank case is the locus of an excessive ac'-.

culation of oil while. the ends are deficient. I I

One of theobjects of the present invention isto provide means for breaking up the aircurrents; produced inside the crank caseby" rotation of the crank shaft and so: assure even distribution- 29 "of oil inthe bottom of the crank caseand; over the surface of. the oil filter; .ifany, positioned therein.

Other objects will appear in the course of I the detailed description now .to be given with reference to the accompanying drawing, in

which: I

Figure l is a partial vertical axial section through one illustrative embodiment of the invention; Figure 2 is a section taken on line 2-2 of Figure 1. I

. The invention will be described with reference to a current type of aviation motor but it is to be understood that it may be applied to any type of motor whatever in which lubricant, accumulating in the bottom of a crank case, is aspirated by a lubricating pump and distributed to the various parts of the motor.

Referring to the various figures of the drawing, there is shown a multiple cylinder block 0. provided with pistons and connecting rods of current design, a crank shaft b driven by the various connecting rods and enclosed in a crank case 0. A lubricating pump d aspirates oil from a reservoir 6 and delivers lubricant to various parts of the motor. Th oil accumulating in the bottom of crank case 0 flows'into a pair of wells h h situated at opposite extremities thereof from I which it is aspirated by a pump f of conventional construction and returned to reservoire. The

crank case is provided with a wire gauze filter i of usual construction acting to prevent impurities passing with the oil into chamber h situated thereunder.

- It has been observed that at high motor speeds,

correspondingly pumps f cease to aspirate lubricant at irregular intervals, 'the. lubricant accumulating. above screen. i. and, more particularly; toward the centerthereofwhere itiscaught up bythe air cur.

rents. produced by r'otationfjof the] crank shaft.

Undesirable accumulations. of. lubricant, there fore, are produced in theorank. case..;

To break up these air currents and assure' even. distribution. of lubricant over. screen. a

perforated plate "is. position'edlf'. substantially as.

shown. in. the drawing in the space between thecrank. shaft and filter The. dimensions.- of the. holes in plate. 9 may,. of course,. vary with the particular motor being used. In. actualpractice. excellent. results are obtained by making the ,di.-. mensionsof. the orifices throughplate g at least 20 times greater. than the. corresponding. orifices through; filter. 21. In a.certain. particular. type of. motor satisfactory resultswerev obtained using. a. filter of. current designa-nda plate ghavingholes, therethrough measuring4. millimeters diam eter.v Diameters less, than 4. millimeters'wmay of course, be used. It is to beunderstood that the,

holes through plate g need not be circularbut may take the form of elongated slots, oval apertures, or the like, it being clearlyunderstood that the function of this plate is to breakup the air currents just above filter 2' while opposing a minimum of resistance to the flow of oil toward the latter.

The distance between elements 9 and i may be varied at will. Good results have been obtained by spacing them at a distance of 15 to 20 millimeters in aviation motors of current design.

7 If the motor includes such elements as compressors, reducers, or valve controls whose supply of lubricant can be distributed before its return to the crank case, conduits such as'y' may be provided for taking care of these oil supplies, said conduits discharging underneath screen 9 and above filter i (if such a filter forms part of the I I assembly).

The invention is not-to crank case assemblies in which a filter is employed. Obviously, screen or bafile g would function equally well to breakup air currents tending be taken as limited to to unevenly distribute the oil in thebottom of a crank case not supplied with a filter. I

In actual test, it is found that aviation motors supplied with air bafiies of the type of' element g show a very "constant oil consumption per horsepower hour of operationirrespective of the f peed of rotation, excessive lubrication at high, I

" construction is preferable.

they need not necessarily extend over the whole length of the crank shaft, though such a form of In certain special types of motors it may be desirable or even ad- 'vantageous, to dimension and position said screen so as to break up the air currents immediately adjacent certain parts of the crank shaft or its bearings.

What I claim is: 1. In a motor provided with a crank shaft, a crank case, a filter positioned in said crank case, and means in said crank case between said filter and crank shaft for breaking up air currents produced inside said crank case during rotation of said crank case, said last named means offering a lesser resistance to fiow of lubricant than said filter, whereby lubricant is permitted to spread evenly over the filter without the formation of uneven accumulation of lubricant by the air currents. a

2. In a motor provided with a crank shaft, a crank case, means for discharging'oil from said crank case; an oil filter positioned inside said crank case above said'discharging means, and

means for breaking up'air currents produced inside said crank case during rotation of the crank shaft, said last named means being positioned in said crank casein spaced relation to and above said oil filter and being independent thereof,

whereby oil is' permittedto spread evenly over the filter without, thefor'mation of uneven accumulations of lubricant by the air currents;

Y '3. In a motor provided with a crank shaft", a

4. In a motor provided with a crank shaft, a crank case, means for discharging oil from said crank case, a filter above said discharging meansv having orifices formed therethrough, and a screen having apertures formed therethrough, the apertures in said screen having dimensions at least twenty times greater than the orifices through said filter, said screen being positioned above said filter, wherebyoil is permitted to spread ,evenly'over the filter without the formation of uneven accumulations of lubricant by the air currents produced by rotation of said crank shaft. a 5. In a motor provided with a crank shaft, a

crank case, means for discharging oil from said crank case, and means between said discharging means and crank shaft for breaking up air currents produced inside said crank case during the rotation of saidcrank shaft, said last named means offering free passage to both oil and the impurities contained therein, whereby oil is permitted to spread evenly on the side of 'said current breaking means opposite the'crank shaft without the formation of uneven accumulations of 'oil by the air currents. a 6.'A structure as defined inclaim' 5fin com bination with means for delivering oil to said crank case at a point situated between said first and second means. a a V '7. In a motor provided with a crank shaft,

a crank case,'an oil filter positioned insidel'said crank case, means between said filter and crank shaft'for' breaking up air'currents produced in-g side said crank case during rotation of said crank shaft, said means. being positionedabove and in spaced relation to said oil filter,and means for delivering on to said crankcase at a point situated between said oil filter and said'means,

whereby oil is permitted to=.'s'pread evenlyover the filter without the formation of uneven accumulations of lubricant by the air currents."

MA C BIRKIGT. 

